Caption: James Webb Space Telescope (JWST). Artwork of the JWST in space against a nebula. This is an infrared telescope that is scheduled to be launched in 2018. It will have a 6.5 metre diameter mirror (yellow), with which it will study the formation of stars and planetary systems, and the history of the universe. By using infrared wavelengths, the JWST will be able to see through much of the dust that obscures visible light. It will also study dark matter, which is thought to form the majority of the matter in the universe.